1. Field of the Invention
This invention is directed to a valve device for use in pressurized flexible hoses to automatically prevent forceful escape of air or other gas from the hose if it becomes disconnected from the primary conduit and then to allow slow release of this gas to gradually return the pressure in the hose to atmospheric pressure. Thus, the noise and whipping action usually associated with sudden loss of pressure in gas hoses is eliminated.
2. Description of the Related Art
The prior art is aware of pneumatic systems which are made up of a source of pressurized gas, usually air, in combination with a primary gas conduit which is detachably connected to a flexible hose by means of a quick-disconnect valve. The downstream or distal end of the flexible hose is connected to an air-powered tool. In such systems of the prior art, disconnection of the flexible hose from the primary gas conduit causes a loud noise which can be harmful to hearing. Also, this rapid decrease in pressure can lead to whipping or lashing of the end of the flexible hose that has become disconnected from the primary conduit. The present invention is designed to eliminate these hazards existing in the prior art systems.
The prior art is also aware of valves which allow the passage of pressurized gas in a distal direction and prevent the sudden backflow of pressurized gas upon elimination of the pressure upstream of the valves. Thus, Great Britain Pat. No. 6738 to Burgess et al published Mar. 30, 1909 discloses a stem fitted with a spring and a plunger having a bypass hole therein to prevent the sudden loss of steam pressure but to allow a gradual reduction in pressure. The spring may be omitted and the device may be operated by gravity. The valve device of this patent is required to be approximately twice the size of the steam conduit and requires the presence of an elongated stem in order to maintain the plunger in proper alignment. U.S. Pat. No. 821,859 to Clegg also teaches a valve which allows air flow in a distal direction. This valve contains a plunger which abuts with a tapered seat. The plunger contains a port running the length of the plunger. When air pressure and the spring force the plunger distally, air flows freely. Upon loss of air pressure upstream of the valve, the plunger is forced against the tapered seat to eliminate sudden loss of pressure downstream of the valve, Air flowing through the port allows a gradual return of the downstream pressure to atmospheric pressure. This valve requires a long axial stem to maintain the alignment of the plunger and, as a consequence, the valve must be bulky. This is suitable for railroad braking systems disclosed in the patent but would not be amenable for the operation of pneumatic powered tools where lightness of weight and smallness of size are essential. Neither of these prior art references addresses the safety problems caused by loud noise and whipping ends of hoses when the hoses suddenly become disconnected from a pressure source.